P-down ZnSTeSe/ZnSe/GaAs heterostructure photodiodes

High-quality quaternary ZnSTeSe epitaxial layers with uniform carrier concentration of 1/spl times/10/sup 17/ cm/sup -3/ were successfully grown on p-GaAs substrates by molecular beam epitaxy. P-down ZnSTeSe/ZnSe/GaAs heterostructure photodiodes were also fabricated. It was found that the maximum quantum efficiency of the fabricated ZnSTeSe photodiodes was around 75% with a large spectral width of 500 nm.